The matrix metalloproteinases (MMPs) are a family of enzymes including interstitial collagenase, neutrophil collagenase, collagenase-3, 72 kDa gelatinase, 92 kDa gelatinase, stromelysin-1, stromelysin-2, stromelysin-3, matrilysin, macrophage metalloelastase, membrane-type metalloproteinase-1 and membrane-type metalloproteinase-2. These enzymes share a common zinc-containing catalytic domain and a pro-sequence which maintains latency. A wide range of cells and tissues can express MMPs in response to activation by inflammatory stimuli such as interleukin-1 or tumour necrosis factor-.alpha. (TNF-.alpha.). Different stimuli can induce overlapping yet distinct repertoires of MMPs and different cell types can respond to the same stimuli by expression of distinct combinations of MMPs. MMPs can attack the protein components of extracellular matrix such as collagens, vitronectin and elastin, and have recently been shown to process membrane proteins such as pro-TNF-.alpha. to release soluble TNF-.alpha.. MMPs are thought to play a central role in the pathology of inflammatory diseases such as rheumatoid arthritis as well as in the growth and metastasis of tumours.
Compounds which have the property of inhibiting the action of MMPs are thought to be potentially useful for the treatment or prophylaxis of conditions involving such tissue breakdown, for example rheumatoid arthritis, osteoarthritis, osteopenias such as osteoporosis, periodontitis, gingivitis, corneal epidermal or gastric ulceration, and tumour metastasis, invasion and growth. MMP inhibitors are also of potential value in the treatment of neuroinflammatory disorders, including those involving myelin degradation, for example multiple sclerosis, as well as in the management of angiogenesis dependent diseases, which include arthritic conditions and solid tumour growth as well as psoriasis, proliferative retinopathies, neovascular glaucoma, ocular tumours, angiofibromas and hemangiomas.
Two known classes of pseudopeptide or peptide mimetic MMP inhibitors have a hydroxamic acid group or a carboxylic group respectively as their zinc binding groups. Many such known MMPs may be represented by the structural formula (IA) ##STR2##
in which X is the zinc binding hydroxamic acid (--CONHOH) or carboxylic acid (--COOH) group and the groups R.sub.1 to R.sub.5 are variable in accordance with the specific prior art disclosures of such compounds.
WO 96/16027 (Syntex/Agouron) discloses a class of MMP inhibitor compounds which can be represented by formula (IA) above. The principal structural characterising feature of the compounds disclosed in WO 96/16027 is the group R.sub.2 which is defined in the publication as being a group R.sup.2 --X-- wherein X is --(CH.sub.2).sub.m --Y--(CH.sub.2).sub.n, Y being O, S or a single bond, m and n being 0, 1, 2, 3 or 4 and m+n being 0, 1, 2, 3, or 4, and R.sup.2 being (inter alia) aryl or heteroaryl, the latter terms including biaryl such as biphenyl and heteroaryl-aryl such as 4-pyridylphenyl.
Another known class of collagenase inhibitors is represented by those disclosed in EP-A-0574758 (Roche), EP-A-0684240 (Roche), and WO 95/33731 (Roche). In general, the compounds disclosed in those publications may be represented by the structural formula (IB): ##STR3##
in which R.sub.1, R.sub.2 and the N-containing ring are variable in accordance with the specific disclosures of the publications.
Foley et. al., Bioorg. Med. Chem Lett. 1996, 6:1905-1910 disclose MMP inhibitors which are C-terminal amido-, N-terminal acyl-dipeptides, wherein the zinc binding group is a mercapto group located in the side chain of the N-terminal amino acid.